Apparatus for drawing metal tubes



Oct. 17, 1933. J. KEMP APPARATUS FOR DRAWING METAL TUBES Filed March 15,1952 Patented Oct. 17, 19 33 V UNITED STATESPATENT OFFICE ApplicationMarch 15, 1932. Serial No..599,001

8 Claims. (Cl. 205-7) This invention relates to a certain new and usefulapparatus for drawing metal tubes, and has for its object to provide, ina manner as hereinafter set forth, an apparatus of the class referredto, so constructed and arranged as to attain at all times a thoroughlyefficient drawing of the tube; to eliminate breakage of the tube duringthe drawing thereof; to reduce to a mini mum missing, chatters,flivvers, and scratches in the tube and packing of the metal in theapparatus during operation of the latter; and obtaining a materialsaving in time, labor and material by effecting the same result in onedrawing operation as was heretofore accomplished in two or more suchoperations.

Further objects of the invention are to provide, in a manner ashereinafter set forth, a tube drawing apparatus for effecting a gradualreduc tion in tubes and which is simple in its construction andarrangement, strong, unusually durable, compact, thoroughly efficient inits use, readily assembled, and comparatively inexpensive tomanufacture.

With the foregoing and otherobjects in view, the invention consists inthe novel construction, combination and arrangement of parts ashereinafter more specifically described and illustrated in theaccompanying drawing. wherein is' shown an embodiment of the invention,butit' is to be understood that changes, variations and modificationscan be resorted vtogwhich fall Figure 5 is a side elevation of a dieforming the 7 other elementof the apparatus.

Referring to the drawing in-detail, the apparatus includes a die 1 whichcontacts with the exterior surface of a metal tube 2 to be graduallyreduced in diameter and increased. in length in a drawing operation bythe apparatus iriaccord ance with this invention.

The die 1 includes a body part 3 formed with a lengthwise extending boreincreasing in diameter from one end to the other and has the endthereofof smallest diameter at the forward end of body part 3. with a series ofinset successively arranged drawingoperation. to prevent the reducingaction.

ward end of the stem 10, and series ofnsucces- The wall of bore 4 isformed.

tapered pipe body reducing portions or surfaces,

5 of equal length. Each follower reducing portion has apart of. itslength corresponding in diameter to a part of the length of an adjacent1 leading reducing portion and the remaining part 60, of its length of adifferent diameter than thatof the remaining part of the length'of; suchadjacent leading reducingportion. The leading end of each followerreducing portion is of greater diameter than the leading end of eachleading reducing portion. The leading end of each follower reducingportion is of less diame ter than the follower end of each, leadingreducing portion thereby providing at the follower end of each leadingportion a shoulder fi-which 7 merges into the forward end of afollowerportion. Each reducing portion gradually increases in diameter from itsforward end to its rear end. The reducing portions 5 are disposed atsuchan inclination with respect to theytube n2 being 7 drawn, as todefine contact edges or points 7 and pockets 8. The function of pockets8 is to allow for the expansion of the tube body. during the on thetubebreakingthe latter.

Theiapparatus also includes a mandrel 9 formed with a stem 10, ajtaperednose 11, a taperedgauge part 12 extended rearwardly-from" nose 11, arounded tube support 13 at thetor sively arranged, 'outset. peripheral,frusto-conh cal pipe body reducing portions 14 of the same length andwhich are. arranged between part 12 lower-portion 14'. Each reducingportion 14 inv creases in diameter from its forward end tcr .v

its rear end. The forward. portionld of the series isof greater diameterthan part 12 and .1 between the rear endof the latter and'the for- Wardreducing portion 14 a peripheral shoulder 16 isprovided. The-shoulders15 and 16 provide tube. contact edges, 1'7; The part 12 isof greaterlength thanany oneofthe reducing portions '14. The leading end ofsupport laj is of greater diameter than the follower end ofthat reducingportion 14 withv which support f 13 merges and it is also of greaterdiameter than any one of the other reducing portions of the series.

The two series of reducing portions coast to effect upon the tube agradually tapering reduction in a successive step-like manner to providea tube body of reduced uniform diameter as it leaves the forward end ofthe die.

The operation of the apparatus is as follows: the mandrel is inserted inthe tube and in this relation-inserted'in the die. As soon as themandrel and tube have been drawn into the die a proper distance, whichis when coacting edges 7 and contact edges 17 are opposite each other,

a further pull on the tubewill cause the two series of reducing portionsto draw 'or reduce and lengthen the tube gradually As 'a'result of theconstruction herein set forth each of the contact edges '7 on the die'together with the pockets 6 and coacting edges 17 of the mandrel will ineffect constitute separate sets of successively acting reducers forgradually reducing the diameter of a tube being drawn and extending thelength thereof with such minimum of breakage in the action thereof, asto constitute a valuable step in advance in this art and whichaccomplishes a long sought for result.

What I claim is:--

1. An apparatus for drawing metal tubes comprising a die formed of abody part formed with a bore increasing in diameter from front to rear,

the wall of said bore being provided with a series of successivelyarranged tapered pipe reducing portions, each gradually increasing in'diameter from front to rear, the diameter at the inner end of a leadingportion being less than the diameter of the front end of a followerportion thereby providing shoulders separ-" ating said portions, and amandrel for extending into said bore and for mounting into the pipe tobe drawn, said mandrel formed intermediate its ends with a series ofsuccessively arranged, peripheral outset, frusto-conical pipe bodyreducing portions separated by'shoulders and coacting during the drawingoperation with'the thereof,- each graduallyincreasi'ng in diameter, eachfollower-portion having itsforward end of'greater diameter than theforward end of an adjacent leading portion, each follower por-' tionhaving'a part of its' length corresponding in'diameter to a part' of'thelength of an adjacent'leading portion and the'remaining' part of itslength beingof a different'diameter than the remaining part ofthe'length of such adjacent'leading portion, the forward end of eachfollower portion being of less diameter than the rear end of "a-leadingportion, said wall'being formed with-a shoul'der'betw'een the forwardend of each follower portion and the rear end of each -leading''po'rtion, the forward portion' of said series of "portions having thatendof smallest diameter flush with the forward "end of said body 'partandthe rear portion of said series of portions having that end 'oflargestdiameter flush Withthe rear'end' of said body part;

series of successively tapered portions lengthwise 3. In an apparatusfor drawing metal tubes, a mandrel provided intermediate its ends with aseries of peripheral, successive, outset, frustoconical portionsextending lengthwise thereof and each of the same length and graduallyincreasing in diameter from front to rear, each of said portions beingof a different diameter throughout with respect to the others, a leadingportion being of less-diameter throughout than that of a followerportion, the forward end of said follower portions providing shouldersmerging into the rear end of the leading portions, said mandrel havingan outset curved peripheral supporting portion for the tube at the innerend of said series, a tapered gauge portion at the outer end of saidseries, a nose extended from said tapered portion and a stem extendedrearwardly from saidsupporting portion.

4. In an apparatus for drawing metal tubes, a mandrel including a stemportion, a work support at the forward end of the stem'portion, atapered gauge spaced forwardly of said support and a series ofperipheral successive, frustoconical work reducing portionsinterposedlbetween the leading end of the work support and thefollowerend of the gauge, each of said portions gradually increasing indiameter from its leading to its follower end and of a differentdiameter throughout with respect to the others, a leading portion beingof different diameter throughout than that of a follower portion, theleading end of said follower portions providing shoulders merging intothe follower end'of the leading portions, the leading end of the worksupport being of greater diameter than the follower end of the rearportion of said series, and the leading end of the forward portion ofsaid series being of greater diameter than the follower end of saidgauge.

5. In an apparatus for drawing metal tubes, 'a mandrel including a stemportion, a work support attheforward end of the stem portion, a taperedgauge spaced forwardly of said support and a series'of peripheralsuccessive,.- frustoconical work reducing portions interposed betweenthe leading end of the work support and thefollower end of the gauge,each of said por-' tions gradually increasing in diameter from itsleading to its follower end and of a different diameter throughout withrespect to the others, a leadingportion being of different diameterthroughout than that of a follower portion, the leading end of saidfollower portions providing shoulders merging into the follower endofthe leading po'rtionathe leading end of the work support being ofgreater diameter than the follower end of the rear portion of saidseries, and the leading end of the forward portion of said series beingof greater diameter than the follower end of said gauge, said gaugebeing of greater length than any one of the portionsof said series, andsaid support being rounded and having its leading end of greaterdiameter than any one of the portions of said series.

6. In an apparatus for drawing metal tubes, a mandrel including a stemportion, a work support at the forward end of the stem portion, atapered gauge spaced forwardly of said support and a series ofperipheral successive, frustoconical work reducing portions interposedbetween the leading end of the work support and the ,followerend of thegauge, each of said portions gradually increasing in diameter from itsleading to its follower end and of a different diameter throughout withrespect to the others,

a leading portion being of different diameter throughout than that of afollower portion, the leading end of said follower portions providingshoulders merging into the follower end of the leading portions, theleading end of the work support being of greater diameter than thefollower end of the rear portion of said series, the

leading end of the forward portion of said se ries being of greaterdiameter than the follower end of said gauge, said gauge being ofgreater length than any one of the portions of said series, said supportbeing rounded and having its leading end of greater diameter than anyone of the portions of said series, and said mandrel including a taperednose extended forwardly from the leading end of said gauge.

7. In an apparatus for drawing metal tubes, a die including a body partformed with a bore increasing in diameter from the front end of the bodypart to the rear end of the latter, the wall of said bore being providedwith an inset series of successive, independent, tapered portionslengthwise thereof, each gradually increasing in diameter from front torear, each follower portion having its leading end of greater diameterthan the leading end of an adjacent leading portion, each of saidportions being free of interruption from front to rear, each followerportion having its leading end of less diameter than the follower end ofan adjacent leadingportion, said wall being formed with an endlessshoulder between the forward end of each follower portion and thefollower end of each leading portion, said shoulders coacting with saidtapered portions to provide spaced points and annular pockets, thelatter being separated by the points.

8. In an apparatus for drawing metal tubes, a mandrel providedintermediate its ends with a series of peripheral, successive, outset,independent, frusto-conical work reducing portions extending lengthwisethereof, each of said portions gradually increasing in diameter fromfrontto rear, each of said portions being of a different diameterthroughout with respect to the others, a leading portion being of lessdiameter throughout than a follower portion, the forward end of saidfollower portions providing flat endless shoulders merging into the rearends of the leading portions, and a tapered gauge portion graduallyincreasing, in diameter from front to rear, the rear end of the gaugeportion being of less diameter than the leading end or the forward workreducing portion of said series, the leading end of the forward workreducing portion of said series providing a flat endless shouldermerging into the follower end of said gauge portion. 7

JOSEPH KEMP.

